The present invention relates to bedding systems, and particularly to bedding systems which heat or cool a person lying in a bed. The invention also relates to methods for selectively heating and cooling a person lying in a bed.
Several bedding devices have been developed previously for providing heat to a person lying in a bed. Electric blankets containing electric heating elements have been used for many years to warm the occupant of a bed. Cooling blankets have also been proposed such as the blanket disclosed in U.S. Pat. No. 4,660,388 to Greene. Greene is directed to a cooling cover having an inflatable pad with plenum chambers at opposite ends. Cool air is generated in a separate unit and directed to the pad and out a number of small air jets on the underside of the pad and against the body of the user.
Cooling devices other than blankets have also been proposed. U.S. Pat. No. 4,006,604 to Seff discloses an air conditioned pillow into which cool air is directed. The cold air passes through layers of permeable cushion material to cool the pillow and its user.
Blankets which provide heat to or remove heat from the user have also been proposed. U.S. Pat. No. 2,504,308 to Donkle is directed to a heating and cooling cover having an embedded coil which is used alternatively as either the evaporator or condenser of a refrigerating system. Another coil located externally from the cover is used alternatively as either the condenser or evaporator. In the Donkle patent the cover or blanket utilizes refrigerant gas in its coils to effect heating or cooling as desired.
U.S. Pat. No. 3,738,702 to Jacobs discloses a device for heating or cooling a person occupying a seat such as a car seat. In the Jacobs device, heating or cooling is effected by cycling a volatile fluid through closed channels in the seat or a portable pad capable of being placed on the seat.
Several problems are inherent in the prior devices. Electric blankets provide sufficient heating, but are incapable of alternatively heating or cooling the user and present a fire hazard. Electric blankets also have no means for selectively providing heat only to the body of the user and providing insulation for the remainder of the heating elements.
The cover disclosed in the Greene patent referenced above actually directs cool air from the inflatable pad onto the user and thus cools the user by convection, which tends to be inefficient. Also, cool air escapes from the pad through each air jet regardless of the position of the user under the cover, with no means for selectively cooling the user.
The cover disclosed in the Donkle patent also heats or cools the entire cover and therefore areas where the user is not located. Thus Donkle also cannot selectively heat or cool the user.
The present invention provides heating or cooling to the occupant of a bed by selective conduction, while insulating the heating or cooling medium in areas where the user is not lying.